Nitrogen doped heat treated and activated hydrothermal carbon: NEXAFS examination of the carbon surface at different temperatures

作者：Latham Kenneth G; Dose Wesley M; Allen Jessica A; Donne Scott W

来源：Carbon, 2018, 128: 179-190.

DOI：10.1016/j.carbon.2017.11.072

Hydrothermal carbons have been shown to have controllable surface functionalization through various post-treatment techniques, which indicates these materials may be tuned for specific applications. For this reason, Near Edge X-ray Absorption Fine Structure (NEXAFS) studies have been conducted on a series of nitrogen doped and non-doped heat treated and activated hydrothermal carbons to further understand the changes in surface functionality with treatment. The NEXAFS carbon K-edge spectrum of the non-doped samples displayed a loss of oxygen functionalities (C=O and C-OH) as well as the furan ring structure with increasing temperature, while C=C bonds from graphitic groups increased. This effect was amplified further upon the addition of phosphoric acid (H3PO4) during activation. The doped hydrothermal carbons displayed similar functionality to the non-doped, although the effect of both heat treatment and activation was diminished. The nitrogen K-edge displayed characteristic peaks for pyridine and imines/amides, with pyrroles located under the broad ionization step. This work represents the first time a series of heat treated and activated hydrothermal carbons have been examined via NEXAFS spectroscopy. Additionally, difference analysis has been applied to the NEXAFS spectra to obtain a deeper understanding in the changes in surface functionality, a previously unused technique for these materials.

• 出版日期2018-3